Ferguson police shot a man who fired on them in Ferguson, Missouri, late Sunday evening, the St. Louis County Police Department said, following the one-year anniversary of the death of Michael Brown.

In an early Monday morning press conference, St. Louis County Police Department Chief Jon Belmar explained that two groups exchanged gunfire on the west side of W. Florissant near the Sam’s Market in Ferguson, amid a protest marking Brown’s death.

A male from one of those groups left, walked across the street, and stopped on the shoulder. Four plainclothes officers in an SUV saw that person, and pulled their vehicle out. The suspect opened fire on the car, hitting the grill and windshield.

St Louis County Police said several gunshots fired by at least two unknown persons were reported. One of the suspects reportedly ran across a parking lot where he was spotted by St. Louis County Police Detectives in an unmarked vehicle. The detectives activated their emergency lights and began driving toward the suspect.

A release from the St. Louis County Police Department said that detectives exited the vehicle and started to run after the suspect. The suspect reportedly turned, and reengaged the detectives, who returned fire. That suspect was wounded several times.

Several objects were thrown at police and some businesses damaged, the St. Louis County Police Department said. A journalist was attacked and robbed in a parking lot. Three St. Louis County police officers were injured: One was struck in the face by a brick, while two others were pepper-sprayed.

Police, with helmets and shields, pushed crowds back and called in tactical units.